1. Field of the Invention
The present invention generally relates to the cooling of heat-generating components in electronic apparatus and, in a preferred embodiment thereof, more particularly relates to the forced air cooling of a closely spaced series of processor modules in a computer server unit.
2. Description of Related Art
As their operating speeds and capacities keep increasing, it is becoming increasingly difficult to provide adequate cooling for processors and other high heat-generating components used in electronic equipment. An example of this problem is in the case of computer devices, such as server units, utilizing closely spaced groups of high speed processor modules. Aggravating this increasing heat dissipation requirement for various computer components as they utilize higher and higher operating speeds is the corresponding requirement of placing the components closer and closer together to reduce the critical signal path lengths of the various components.
For example, in the case of computer processor modules the customary method of dissipating processor operating heat has been to place a heat sink member, typically a finned metal heat exchanger, on a side of the processor and flow a stream of cooling air across the heat sink member to carry away heat conducted thereto by the processor. However, when it becomes necessary to group multiple high speed processors in a facing, side-by-side row arrangement such as in a multi-processor server unit the use of this traditional heat dissipation technique becomes impractical for two primary reasons.
First, the requirement of positioning the multiple processors close enough to one another to avoid undesirably long signal path lengths to and from the processors makes it difficult, due to the side-to-side spacing of adjacent pairs of processors, to mount sufficiently large heat sink members on side surfaces of the processors. Second, it is desirable to position the DC/DC power converters (also commonly referred to as voltage regulation modules or circuit boards, or simply voltage regulators) which are used in conjunction with the processors as close to their associated processors as possible. This is desirable because instantaneous power change requirements found in modern microprocessors require short, low inductance supply paths between the voltage regulators and the processors. Accordingly, a highly preferable orientation of these voltage regulation circuit boards is one in which they are interdigitated with their associated processor modules--i.e., placed in the gaps between the processors in a parallel relationship with the processors. This preferred placement of the DC/DC convertors further diminishes the space between adjacent processors which would otherwise be available for their side-mounted heat sink members.
In addition to these two design problems which are presented in instances where it is desirable to position processors or other high heat-generating electronic components in a closely spaced array, the very positioning of the components in such a closely spaced array substantially limits the cooling air flow directional design flexibility. For example, in the case where the processors with their conventional side-mounted heat sinks are arranged in a closely spaced row in which the parallel processors face one another, the cooling air flow must be directed parallel to the processor sides so that it can pass through the spaces between the adjacent facing pairs of processors. The cooling air flow cannot be directed perpendicular to the processor sides since this would substantially preclude cooling air flow across the side-mounted processor heat sinks. An additional concern is the fact that the DC/DC convertor modules can generate a considerable amount of operating heat as well.
As can readily be seen from the foregoing, a need exists for improved heat dissipation apparatus useable in conjunction with closely spaced arrays of high heat-generating electronic components such as computer processor modules. It is to this need that the present invention is directed.